2& PUPA OF ZULU LAND TSETSE. 



From the examination of a series of Tsetse-fly pupte from 

 Zululand, kindly presented to the British Museum by Colonel 

 Bruce, I am enabled to give the following description of the pupal 

 stage (Fig. 7) in the only species of which the life-history has yet 

 been observed. As will be seen from remarks in Chapter IV.,* 

 the identity of the species is a little uncertain, though it must be 

 either Glossina morsitans, Westw., or Gl. pallidipes, Austen. 



The extreme length of the pupa in this species varies from 

 6-^- to 7 millimetres (3 to 3 J lines), while its greatest width is from 

 3^- to 3| millimetres (1§ to 1| lines). The colour is dark brown, 

 except in the case of the last segment which is deep black, repre- 

 senting what Bruce calls the "black hood" in the larva. In 

 shape the pupa is very remarkable, owing to the peculiar develop- 

 ment of the last segment. Instead of exhibiting the regular 

 contour seen in the Muscid pupa of the ordinary "barrel- 

 shaped " type (as in the house-fly, blow-fly, atid green-bottle flies), 

 and although the main portion of the pupa is an elliptical oval 

 with the anterior end somewhat obtuse, similar to the pupee of 

 the types referred to, the posterior extremity (last segment) is 



mother was discovered by Portchiuski in the case of Danyphora pratorum, 

 Mg., which also belongs to the Muscinse, i.e., to the Muscidffi in the most 

 restricted sense. The species in question deposits in the dung of cattle 

 a large larva, which is retained within a matrix-like receptacle in the 

 body of the mother until it reaches the third stage. After extrusion the 

 larva "very soon reaches its full growth and goes underground for its 

 further development" (C/. Osten Sacken, loc. cit., p. 25). As to the 

 connection between the mode of development of the Pupipara and that 

 of the flies just mentioned, Osten Sacken writes as follows {loc. cit., pp. 

 26-27): — "Hitherto the Pupipara had an isolated position among the 

 Diptera. The modes of larval evolution of Musca corvina and Dasyphora 

 pratorum, discovered by Mr. Portchinski, bridge over the interval. He 

 even ventures the hypothesis that the Pupipara began by being 

 copropbagous in their larval state, and laid an almost full-grown larva 

 like that of the two above-mentioned flies. Later, owing to the parasitic 

 mode of life of the imago and the diminution of the powers of flight 

 necessary for providing the proper environments for the larvse, those 

 changes in the mode of evolution of the larvae were produced which 

 distinguish the Pupipara now." It is not yet known whether in the 

 Tsetse and the other Muscidse, which produce a single more or less adult 

 larva at a birth, the oviduct of the female is provided with glands by the 

 secretion of which the larva is nourished, as in the case of the so-called 

 Pupipara ; but it must be remarked that, whatever be the case with regard 

 to the latter, Portchinski's hypothesis will not serve to explain the origin 

 of the mode of development of the Tsetse, as exhibited by the Zululand 

 species, which presents an even closer approximation to that of the 

 Pupipara, than does the development of either Musca corvina or Dasyphora 

 pratorum. For the Tsetse, although feeding on blood, is not parasitic in 

 the ordinary sense of the term, while its powers of flight have been in no 

 way affected by its mode of life. 

 ♦ See page 89. 



